If the only leafy green vegetable you're familiar with is iceberg lettuce, you don't know what you're missing. There's a world of greens available that offers you more nutrients than iceberg.

Greens are quite versatile vegetables. They are easy to prepare and can be boiled or steamed -- or even eaten raw. They can be part of a crisp salad or a hearty soup. Greens are tasty and full of vitamins and nutrients too. Here's a list of some important nutrients you get from leafy greens:

Calcium. Calcium builds strong bones and teeth. This is especially important in preventing osteoporosis, a disease that weakens bones and can lead to fractures.

Beta-carotene. This substance is made into vitamin A in the body, and plays an important role in vision, bone growth, reproduction, and cell growth.

Phytochemicals. These chemicals are found in plants, especially dark green ones. Research shows that certain phytochemicals may help prevent some cancers and heart disease

A greens guide

Before you eat any greens, it's important to wash them in cool water. Then dry them in a salad spinner, or shake them gently in a colander.

You can find many different greens at your local supermarket or at a farm stand. Keep in mind that the fresher greens are, the better they taste. Look for crisp leaves. Here is a guide to help you get started.

Arugula. With its spicy taste, arugula livens up any salad. Serve raw on sandwiches or burritos. Or saute it in a small amount of olive oil for five seconds -- any longer and arugula loses its flavor. Then toss it with some cooked pasta.

Beet greens. Cut off the beets and the stems of this slightly sweet green. Steam the greens until tender.

Bok choy. This celery-like vegetable is mild in flavor and big on crunch. Stir-fry it with Asian flavorings, such as soy or hoisin sauce.

Broccoli rabe (also called broccoli raab and rapini). Italians saute this form of broccoli in olive oil with garlic. You may want to steam it first to remove some of its bitter taste.

Collard greens. Collard greens have thick, tough leaves, so they need to be cooked longer than most greens to become tender. You should boil them for about 15 minutes. Collard greens are high in calcium and are delicious -- as a side dish or in stews.

Dandelion greens. Before they sprout those familiar bright yellow flowers, dandelion greens make great eating. Add young greens to salads. Saute older ones in a little olive oil with some minced garlic, and serve as a side dish.

Kale. It's best to steam kale for five minutes, because it has a bitter flavor. Then quickly saute it with olive oil and vinegar. Kale tastes especially good in tomato-based soups and stews. Kale has especially high levels of antioxidants.

Mustard greens. The best thing about mustard greens is that they do not lose their spicy flavor when cooked. They are a great accent to stir-fry dishes and go well with strong flavors such as vinegar and ginger.

Swiss chard. Swiss chard comes in two kinds: red and white. Red has a stronger flavor. Both types are high in vitamins A and C. Wash chard especially well, because it traps dirt in its leaves. Steamed or sauteed, it gives any meal extra nutrition and flavor.

Quick cooking

Be careful not to overcook greens; you'll get fewer nutrients if you do. Greens are done when they are barely tender. Most greens cook in 5 to 15 minutes, depending on the toughness of the leaves.

On your next trip to the grocery store, be adventurous in the produce aisle. You might find a green you don't like, but chances are you'll also discover some tasty ones. Experiment with the greens you like. Add them to rice or risotto dishes, or toss them with spaghetti. Or, use them to top homemade pizza. There's no wrong way to eat them, and you can't beat the nutritional rewards.